Measurement of hydrogen sulfide during breath testing

Abstract

Described herein are methods of detecting levels hydrogen sulfide (H2S) to diagnose H2S positive disease or conditions. Examples of H2S positive diseases and conditions include small intestinal bacterial overgrowth, diarrhea, fatigue, bowel urgency and abdominal pain. The H2S level can guide treatments for subjects who have high levels of H2S.

What is claimed is: 
     
       1. A method for selecting a therapy for a subject, and treating the subject, comprising:
 obtaining a biological sample from a subject; 
 measuring the hydrogen sulfide (H 2 S) level in the biological sample during a test; 
 selecting a therapy for an H 2 S positive condition when the H 2 S level is higher than 1.2 ppm cut-off at any point during the test; and 
 administering the selected therapy to the subject to treat the H 2 S positive condition, wherein the H 2 S therapy comprises rifaximin, 
 wherein the H 2 S positive condition is selected from the group consisting of H 2 S positive diarrhea, H 2 S positive fatigue, H 2 S positive bowel urgency, H 2 S positive abdominal pain and combinations thereof, 
 wherein the biological sample is a breath sample. 
 
     
     
       2. The method of  claim 1 , wherein the subject has or is suspected of having irritable bowel syndrome. 
     
     
       3. The method of  claim 1 , wherein H 2 S is measured using a four gas detection device or system and the four gases are H 2 , CH 4 , H 2 S, and CO 2 . 
     
     
       4. The method of  claim 1 , wherein H 2 S is measured after the subject ingests a controlled quantity of a substrate selected from the group consisting of lactulose, xylose, lactose, glucose, fructose and combinations thereof.